What is steem power?

Could you please elaborate on what Steem Power is? I understand it's related to the Steem blockchain and its ecosystem, but I'm not entirely clear on how it functions and what its significance is within the platform. Can you explain how Steem Power is earned, how it's used, and what benefits or advantages it provides to holders? Additionally, is there a limit to how much Steem Power can be accumulated, and how does it differ from other cryptocurrencies or tokens?